Organic light-emitting illumination apparatus with reflector

ABSTRACT

An organic light-emitting illumination apparatus that may be easily manufactured and may provide high-brightness illumination, and a method of manufacturing the same. The organic light-emitting illumination apparatus includes: a first flexible substrate; a first electrode disposed on the first flexible substrate and configured to transmit light; an intermediate layer disposed on the first electrode and including a light emission layer; a second electrode disposed on the intermediate layer and configured to transmit light; a second flexible substrate disposed on the second electrode; and a reflector interposed between the second flexible substrate and the second electrode to correspond to a first region of the second flexible substrate.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority from and the benefit of Korean PatentApplication No. 10-2014-0139064, filed on Oct. 15, 2014, which is herebyincorporated by reference for all purposes as if fully set forth herein.

BACKGROUND

Field

Exemplary embodiments of the present invention relate to an organiclight-emitting illumination apparatus and a method of manufacturing thesame, and more particularly, to an organic light-emitting illuminationapparatus that may be easily manufactured and may providehigh-brightness illumination, and a method of manufacturing the same.

Discussion of the Background

In general, an organic light-emitting device may be used as a displaydevice of an organic light-emitting display apparatus. Recently,research has been conducted to manufacture an illumination apparatus(not a display apparatus) by using an organic light-emitting device.

However, in the case of an organic light-emitting illuminationapparatus, that is, an illumination apparatus including an organiclight-emitting device, sufficiently bright light for illumination maynot be emitted.

The above information disclosed in this Background section is only forenhancement of understanding of the background of the inventive concept,and, therefore, it may contain information that does not form the priorart that is already known in this country to a person of ordinary skillin the art.

SUMMARY

Exemplary embodiments of the present invention provide an organiclight-emitting illumination apparatus which may be easily manufacturedand may provide high-brightness illumination, and a method ofmanufacturing the same.

Additional aspects will be set forth in part in the description whichfollows and, in part, will be apparent from the description, or may belearned by practice of the presented exemplary embodiments.

An exemplary embodiment of the present invention discloses an organiclight-emitting illumination apparatus including: a first flexiblesubstrate; a first electrode disposed on the first flexible substrateand configured to transmit light; an intermediate layer disposed on thefirst electrode and including a light emission layer; a second electrodedisposed on the intermediate layer and configured to transmit light; asecond flexible substrate disposed on the second electrode; and areflector interposed between the second flexible substrate and thesecond electrode to correspond to a first region of the second flexiblesubstrate.

An exemplary embodiment of the present invention also discloses a methodof manufacturing an organic light-emitting illumination apparatus,including: preparing a first flexible substrate; forming a firstelectrode configured to transmit light on the first flexible substrate;forming an intermediate layer, including a light emission layer, on thefirst electrode; forming a second electrode configured to transmit lightonto the intermediate layer; preparing a second flexible substrate;forming a reflector corresponding to a first region of the secondflexible substrate; and attaching the first flexible substrate and thesecond flexible substrate such that the reflector faces the secondelectrode.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory and areintended to provide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this specification, illustrate embodiments of the invention, andtogether with the description serve to explain the principles of theinvention.

FIG. 1, FIG. 2, and FIG. 3 are cross-sectional views schematicallyillustrating processes of a method of manufacturing an organiclight-emitting illumination apparatus according to an exemplaryembodiment.

FIG. 4 is a cross-sectional view schematically illustrating an exampleof use of an organic light-emitting illumination apparatus of FIG. 3.

FIG. 5 is a cross-sectional view schematically illustrating an organiclight-emitting illumination apparatus according to another exemplaryembodiment.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

The invention is described more fully hereinafter with reference to theaccompanying drawings, in which embodiments of the invention are shown.This invention may, however, be embodied in many different forms andshould not be construed as limited to the embodiments set forth herein.Rather, these embodiments are provided so that this disclosure isthorough, and will fully convey the scope of the invention to thoseskilled in the art. In the drawings, the size and relative sizes oflayers and regions may be exaggerated for clarity. Like referencenumerals in the drawings denote like elements.

It will be understood that when an element such as a layer, film, regionor substrate is referred to as being “on” another element, it can bedirectly on the other element or intervening elements may also bepresent. In contrast, when an element is referred to as being “directlyon” another element, there are no intervening elements present. It willbe understood that for the purposes of this disclosure, “at least one ofX, Y, and Z” can be construed as X only, Y only, Z only, or anycombination of two or more items X, Y, and Z (e.g., XYZ, XYY, YZ, ZZ).

FIGS. 1 to 3 are cross-sectional views schematically illustratingprocesses of a method of manufacturing an organic light-emittingillumination apparatus according to an exemplary embodiment.

First, a stack structure is formed, as illustrated in FIG. 1. In detail,a first flexible substrate 10 is prepared, and a first electrode 20configured to transmit light is formed on the first flexible substrate10. Thereafter, an intermediate layer 30, including a light emissionlayer, is formed on the first electrode 20, and then a second electrode40 configured to transmit light is formed on the intermediate layer 30.

The first flexible substrate 10 has flexibility and transmits light. Toprovide these characteristics, the first flexible substrate 10 mayinclude a polymer material, for example, polyimide. According to anexemplary embodiment, the first flexible substrate 10 may have amultilayer structure, or various other modified structures, such as analternate stack structure of inorganic layers and organic layers. Also,the first flexible substrate 10 may have a film shape.

The first electrode 20 may be formed of a material capable oftransmitting light. The first electrode 20 may be formed of atransparent electrode material, such as indium tin oxide (ITO), indiumzinc oxide (IZO), zinc oxide (ZnO), or indium oxide (In₂O₃). Accordingto an exemplary embodiment, an auxiliary layer, such as a buffer layer,may be formed on the first flexible substrate 10, and then the firstelectrode 20 may be formed on the auxiliary layer.

The intermediate layer 30 is formed on the first electrode 20. Theintermediate layer 30 may include at least a light emission layer, andmay be formed of a low-molecular organic material or a high-molecularorganic material.

When the intermediate layer 30 is formed of a low-molecular organicmaterial, the intermediate layer 30 may have a stack structure includinga hole injection layer (HIL), a hole transport layer (HTL), an organicemission layer (EML), an electron transport layer (ETL), and an electroninjection layer (EIL). In this case, the intermediate layer 30 mayinclude an organic material, such as copper phthalocyanine (CuPc),N,N′-Di(naphthalene-1-yl)-N,N′-diphenyl-benzidine (NPB), ortris-8-hydroxyquinoline aluminum (Alq3). The intermediate layer 30,including a low-molecular organic material, may be formed by mask vacuumdeposition.

When the intermediate layer 30 is formed of a high-molecular organicmaterial, the intermediate layer 30 may include a hole transport layerand an organic emission layer. In this case,poly-3,4-ethylendioxythiophene (PEDOT) may be used for the holetransport layer, and a high-molecular organic material, such aspoly-phenylenevinylene (PPV) or polyfluorene, may be used for theorganic emission layer.

The organic emission layer included in the intermediate layer 30 mayemit white light, or may include a red emission layer emitting redlight, a green emission layer emitting green light, and a blue emissionlayer emitting blue light.

The second electrode 40 may be formed on the intermediate layer 30 andmay also be formed of a material capable of transmitting light. Indetail, the second electrode 40 may also be formed of a transparentelectrode material, such as ITO, IZO, ZnO, or In₂O₃.

Before, during, or after the process of preparing the stack structureincluding the first flexible substrate 10, as illustrated in FIG. 2, asecond flexible substrate 50 is prepared, and a reflector 55 is formedon the second flexible substrate 50 to correspond to a first region ofthe second flexible substrate 50.

The second flexible substrate 50 has flexibility and transmits light. Toprovide these characteristics, the second flexible substrate 50 mayinclude a polymer material, for example, polyimide. According to anexemplary embodiment, the second flexible substrate 50 may have amultilayer structure, and may have various modified structures, such asan alternate stack structure of inorganic layers and organic layers.Also, the second flexible substrate 50 may have a film shape.

In order to reflect light, the reflector 55 may be formed of argentum(Ag), magnesium (Mg), aluminum (Al), platinum (Pt), palladium (Pd),aurum (Au), nickel (Ni), neodymium (Nd), iridium (Ir), chromium (Cr),lithium (Li), calcium (Ci), lithium fluoride (LiF)/Ca, LiF/Al, or anycombination thereof.

After the stack structure, including the first flexible substrate 10illustrated in FIG. 1 and the stack structure including the secondflexible substrate 50 illustrated in FIG. 2, is prepared, the stackstructures are attached as illustrated in FIG. 3. In detail, the firstflexible substrate 10 and the second flexible substrate 50 are attachedsuch that the reflector 55 on the second flexible substrate 50 faces thesecond electrode 40 on the first flexible substrate 10. The firstflexible substrate 10 and the second flexible substrate 50 may beattached in various ways. For example, as illustrated in FIG. 3, thefirst flexible substrate 10 and the second flexible substrate 50 may beattached by using a sealant 70 that is interposed between the firstflexible substrate 10 and the second flexible substrate 50, and islocated along edges thereof to cover the intermediate layer 30. Inaddition to being used to attach the first flexible substrate 10 and thesecond flexible substrate 50, the sealant 70 may be used to protect theintermediate layer 30 from impurities such as external moisture oroxygen.

According to an exemplary embodiment, unlike the illustration of FIG. 3,at least a portion of the first electrode 20 or the second electrode 40may extend outside the sealant 70 so that an electrical signal may betransferred to the first electrode 20 or the second electrode 40. Also,the organic light-emitting illumination apparatus may have variousmodified configurations, such as a configuration in which the organiclight-emitting illumination apparatus does not include the sealant 70and the first flexible substrate 10 and the second flexible substrate 50may extend, contact each other, and are attached.

The organic light-emitting illumination apparatus may be used in variousways. For example, the organic light-emitting illumination apparatus maybe used as an illumination apparatus in an unfolded state as illustratedin FIG. 3, or may be used as an illumination apparatus in a state ofbeing folded a plurality of times as illustrated in FIG. 4. When theorganic light-emitting illumination apparatus is used as illustrated inFIG. 3, light is emitted from a portion corresponding to the reflector55 in the −y direction from the reflector 55 toward the first flexiblesubstrate 10. That is, light generated at the intermediate layer 30 isemitted to the outside through the first flexible substrate 10 from theportion corresponding to the reflector 55. Regarding the other portionsof the second flexible substrate 50 corresponding to the reflector 55,light generated at the intermediate layer 30 is emitted to the outsidethrough both the first flexible substrate 10 and the second flexiblesubstrate 50. Thus, if only one side is to be illuminated at the portioncorresponding to the reflector 55 and both sides are to be illuminatedat the residual portion thereof, the organic light-emitting illuminationapparatus may be used in the unfolded state illustrated in FIG. 3.

If illumination for emitting high-brightness light in a particulardirection is necessary, the organic light-emitting illuminationapparatus may be used in a folded state, as illustrated in FIG. 4. Indetail, the first flexible substrate 10 and the second flexiblesubstrate 50 may be bent and folded a plurality of times to provide alight emission area corresponding to the reflector 55. In this case,because one edge (in the +x direction) of the reflector 55 is adjacentto one edge (in the +x direction) of the second flexible substrate 50,as illustrated in FIG. 3, when the portion of the second flexiblesubstrate 50 corresponding to the reflector 55 is not covered by theresidual portion of the second flexible substrate 50 and the firstflexible substrate 10, as illustrated in FIG. 4, the organiclight-emitting illumination apparatus corresponding to the area of thereflector 55 may be implemented.

In this case, as illustrated in FIG. 4, a light L1 emitted from theportion corresponding to the reflector 55 of the intermediate layer 30including the light emission layer is emitted (in the −y direction)through the portion of the second flexible substrate 50 notcorresponding to the reflector 55 and the first flexible substrate 10,after or without being reflected by the reflector 55. In this process,the light L1 is emitted to the outside after penetrating the firstflexible substrate 10 a plurality of times. In some cases, depending onthe number of times of folding the organic light-emitting illuminationapparatus, the light L1 is emitted to the outside after also penetratingthe second flexible substrate 50 a plurality of times.

Lights L2 and L3 among lights L2, L2′, L3, and L3′ emitted from theportion not corresponding to the reflector 55 of the intermediate layer30 including the light emission layer propagate directly in the samedirection (the −y direction) as the light L1, and are emitted to theoutside, while the other lights L2′ and L3′ propagate in the direction(the +y direction) toward the reflector 55, are reflected by thereflector 55, propagate in the same direction (the −y direction) as thelight L1, and are emitted to the outside.

In the case of the organic light-emitting illumination apparatusaccording to the exemplary embodiment, when the first flexible substrate10 and the second flexible substrate 50 are bent and folded a pluralityof times to provide a light emission area corresponding to the reflector55 as illustrated in FIG. 4, because all the lights L1, L2, L2′, L3, andL3′ propagate in the same direction (the −y direction), ahigh-brightness organic light-emitting illumination apparatus may beimplemented. In this case, because the intensity of an electrical signalapplied to emit light at a sufficient brightness level is not increased,and the first flexible substrate 10 and the second flexible substrate 50are simply bent and folded a plurality of times, a reduction of thelifetime of an organic light-emitting device may be effectivelyprevented.

Instead of forming the reflector 55 in the first region on the secondflexible substrate 50, the first electrode 20 or the second electrode 40may be formed as a reflective electrode in the first region, and formedas a transparent electrode in other regions. However, in this case, theprocess of forming the first electrode 20 or the second electrode 40 maybe complicated, and thus, the manufacturing yield of organiclight-emitting illumination apparatuses may be significantly reduced.

However, in the case of the method of manufacturing the organiclight-emitting illumination apparatus according to the exemplaryembodiment, the first electrode 20 or the second electrode 40 need onlybe formed of a material capable of transmitting light in the entireregion. Also, the reflector 55 may be formed only in the first region onthe second flexible substrate 50 by deposition or sputtering. Thus, inthe case of the method of manufacturing the organic light-emittingillumination apparatus according to the exemplary embodiment, becausethe manufacturing process is simple, the manufacturing yield may besignificantly increased.

When a stack structure is formed on the first flexible substrate 10, abuffer layer 45 may be further formed on the second electrode 40, asillustrated in FIG. 1. In this case, as illustrated in FIG. 3, the firstflexible substrate 10 and the second flexible substrate 50 may beattached such that the reflector 55 faces the buffer layer 45.

Because the reflector 55 is formed only in the first region that is apartial region of the second flexible substrate 50 when the firstflexible substrate 10 and the second flexible substrate 50 are attached,if the buffer layer 45 is not present, the first flexible substrate 10and the second flexible substrate 50 may not be smoothly attached. Forexample, in the vicinity of the edge of the reflector 55, due to a stepdifference caused by the reflector 55, an empty space may exist betweenthe second electrode 40 and the second flexible substrate 50. Also,because the adhesive force between the reflector 55 and the secondelectrode 40 is not strong, delamination may occur between the reflector55 and the second electrode 40 in the process of using the organiclight-emitting illumination apparatus after completion of themanufacturing process.

However, when the buffer layer 45 is formed on the second electrode 40and the reflector 55 is brought into contact with the buffer layer 45,the buffer layer 45 and the reflector 55 may be smoothly attached, andthus, the overall stability of the organic light-emitting illuminationapparatus may be significantly increased. In particular, if the bufferlayer 45 is formed of an elastic material, it may be possible to preventthe occurrence of a step difference caused by the reflector 55 when thefirst flexible substrate 10 and the second flexible substrate 50 areattached. The buffer layer 45 may be formed of an organic material. Indetail, the buffer layer 45 may be formed of a hole transport materialthat may be included in the intermediate layer 30. A deposition processis performed in the process of forming the first electrode 20, theintermediate layer 30, and the second electrode 40 on the first flexiblesubstrate 10. Thus, because a deposition process is also performed whenthe buffer layer 45 is formed of a hole transport material, ease ofmanufacturing may be further increased.

When the buffer layer 45 is formed, because the first flexible substrate10 and the second flexible substrate 50 are attached, a first thicknesst1 of the buffer layer 45 in the first region of the second flexiblesubstrate 50, that is, the first thickness t1 of the buffer layer 45 ata portion corresponding to the reflector 55, may be smaller than asecond thickness t2 of the buffer layer 45 in the second region of thesecond flexible substrate 50. Accordingly, the occurrence of a stepdifference resulting from the existence of the reflector 55 in theorganic light-emitting illumination apparatus may be effectivelyprevented. According to an exemplary embodiment, the buffer layer 45 maybe formed on the entire region of the second electrode 40.

Although the method of manufacturing the organic light-emittingillumination apparatus has been described, exemplary embodiments are notlimited thereto and the inventive concept may also include the organiclight-emitting illumination apparatus.

An organic light-emitting illumination apparatus according to anexemplary embodiment may have, for example, the configuration shown inFIG. 3. The organic light-emitting illumination apparatus according tothe exemplary embodiment may include a first flexible substrate 10, afirst electrode 20, an intermediate layer 30, a second electrode 40, asecond flexible substrate 50, and a reflector 55.

The first electrode 20 that is capable of transmitting light and isformed on the first flexible substrate 10 and the second electrode 40that is capable of transmitting light and is formed on the secondflexible substrate 50 are disposed to face each other. The intermediatelayer 30, including a light emission layer, is interposed between thefirst electrode 20 and the second electrode 40. In this case, thereflector 55 is interposed between the second flexible substrate 50 andthe second electrode 40 to correspond to a first region of the secondflexible substrate 50.

The organic light-emitting illumination apparatus may be used in variousways. For example, the organic light-emitting illumination apparatus maybe used as an illumination apparatus in an unfolded state as illustratedin FIG. 3, or may be used as an illumination apparatus in a state ofbeing bent a plurality of times as illustrated in FIG. 4. When theorganic light-emitting illumination apparatus is used as illustrated inFIG. 3, light is emitted from a portion corresponding to the reflector55 in a direction (the −y direction) from the reflector 55 toward thefirst flexible substrate 10. That is, light generated at theintermediate layer 30 is emitted to the outside through the firstflexible substrate 10 from the portion corresponding to the reflector55. Regarding the other portions of the second flexible substrate 50corresponding to the reflector 55, light generated at the intermediatelayer 30 is emitted to the outside through both the first flexiblesubstrate 10 and the second flexible substrate 50. Thus, if only oneside is to be illuminated at the portion corresponding to the reflector55, and both sides are to be illuminated at the residual portionthereof, the organic light-emitting illumination apparatus may be usedin an unfolded state, as illustrated in FIG. 3.

If illumination is needed for emitting light having a high brightnesslevel in a particular direction, the organic light-emitting illuminationapparatus may be used in a folded state, as illustrated in FIG. 4. Indetail, the first flexible substrate 10 and the second flexiblesubstrate 50 may be bent and folded a plurality of times to provide alight emission area corresponding to the reflector 55. In this case,since one edge (in the +x direction) of the reflector 55 is adjacent toone edge (in the +x direction) of the second flexible substrate 50 asillustrated in FIG. 3, when the portion of the second flexible substrate50 corresponding to the reflector 55 is not covered by the residualportion of the second flexible substrate 50 and the first flexiblesubstrate 10, as illustrated in FIG. 4, the organic light-emittingillumination apparatus corresponding to the area of the reflector 55 maybe implemented.

In this case, as illustrated in FIG. 4, a light L1 emitted from theportion corresponding to the reflector 55 of the intermediate layer 30including the light emission layer is emitted (in the −y direction)through the portion of the second flexible substrate 50 notcorresponding to the reflector 55 and the first flexible substrate 10,after or without being reflected by the reflector 55. In this process,the light L1 is emitted to the outside after penetrating the firstflexible substrate 10 a plurality of times. In some cases, depending onthe number of times of folding the organic light-emitting illuminationapparatus, the light L1 is emitted to the outside after also penetratingthe second flexible substrate 50 a plurality of times.

Lights L2 and L3 among lights L2, L2′, L3, and L3′ emitted from theportion not corresponding to the reflector 55 of the intermediate layer30 including the light emission layer propagate directly in the samedirection (the −y direction) as the light L1 and are emitted outside,while the other lights L2′ and L3′ propagate in the direction (the +ydirection) toward the reflector 55, are reflected by the reflector 55,propagate in the same direction (the −y direction) as the light L1, andare emitted to the outside.

In the case of the organic light-emitting illumination apparatusaccording to the exemplary embodiment, when the first flexible substrate10 and the second flexible substrate 50 are bent and folded a pluralityof times to provide a light emission area corresponding to the reflector55 as illustrated in FIG. 4, since all the lights L1, L2, L2′, L3, andL3′ propagate in the same direction (−y direction), a high-brightnessorganic light-emitting illumination apparatus may be implemented. Inthis case, because the strength of an electrical signal applied to emitsufficiently bright light is not increased, but the first flexiblesubstrate 10 and the second flexible substrate 50 are simply bent andfolded a plurality of times, a reduction of the lifetime of an organiclight-emitting device may be effectively prevented.

Instead of disposing the reflector 55 in the first region on the secondflexible substrate 50, the first electrode 20 or the second electrode 40may be formed as a reflective electrode in the first region, and formedas a transparent electrode in regions other than the first region.However, in this case, the process of forming the first electrode 20 orthe second electrode 40 may be overly-complicated, and thus, themanufacturing yield of organic light-emitting illumination apparatusesmay be significantly reduced.

However, in the case of the organic light-emitting illuminationapparatus according to the exemplary embodiment, in the manufacturingprocess thereof, the first electrode 20 or the second electrode 40 hasonly to be formed of a material capable of transmitting light in theentire region. Also, the reflector 55 may be formed only in the firstregion on the second flexible substrate 50 by deposition or sputtering.Thus, in the case of the organic light-emitting illumination apparatusaccording to the exemplary embodiment, because the manufacturing processthereof is simple, the manufacturing yield may be significantlyincreased.

As illustrated in FIG. 3, the organic light-emitting illuminationapparatus may further include a buffer layer 45 that is interposedbetween the second flexible substrate 50 and the second electrode 40,and between the reflector 55 and the second electrode 40. If the bufferlayer 45 is not present, an empty space may exist between the secondelectrode 40 and the second flexible substrate 50 in the vicinity of theedge of the reflector 55 as a result of a step difference caused by thereflector 55. Also, because the adhesive force between the reflector 55and the second electrode 40 is not strong, delamination may occurbetween the reflector 55 and the second electrode 40 in the process ofmanufacturing or using the organic light-emitting illuminationapparatus.

However, as a result of the buffer layer 45 being interposed between thesecond flexible substrate 50 and the second electrode 40 and between thereflector 55 and the second electrode 40, the buffer layer 45 and thereflector 55 may be smoothly attached and thus the overall stability ofthe organic light-emitting illumination apparatus may be significantlyincreased. In particular, when the buffer layer 45 is formed of anelastic material, it may be possible to prevent the occurrence of a stepdifference caused by the reflector 55 between the second electrode 40and the second flexible substrate 50. The buffer layer 45 may be formedof an organic material. In detail, the buffer layer 45 may be formed ofa hole transport material that may be included in the intermediate layer30.

In the case of the buffer layer 45, as illustrated in FIG. 3, the firstthickness t1 of the buffer layer 45 in the first region of the secondflexible substrate 50, that is, the first thickness t1 of the bufferlayer 45 at the portion corresponding to the reflector 55, may be lessthan the second thickness t2 of the buffer layer 45 in the second regionof the second flexible substrate 50. Accordingly, the occurrence of astep difference due to the existence of the reflector 55 in the organiclight-emitting illumination apparatus may be effectively prevented.According to an exemplary embodiment, the buffer layer 45 may be formedto correspond to the entire region of the second electrode 40.

Although FIGS. 3 and 4 illustrate that one edge of the reflector 55 isadjacent to one edge of the second flexible substrate 50, exemplaryembodiments are not limited thereto. For example, the reflector 55 maybe located at a center portion of the second flexible substrate 50, asillustrated in FIG. 5. In this case, a portion of one side of thereflector 55 and a portion of other side thereof are folded around theportion of the second flexible substrate 50 corresponding to thereflector 55 to cover the portion of the second flexible substrate 50corresponding to the reflector 55, so that the organic light-emittingillumination apparatus may be used to emit high-brightness light.

As described above, according to the above-described exemplaryembodiments, an organic light-emitting illumination apparatus may beeasily manufactured to provide high-brightness illumination.

It will be apparent to those skilled in the art that variousmodifications and variation can be made in the present invention withoutdeparting from the spirit or scope of the invention. Thus, it isintended that the present invention cover the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

What is claimed is:
 1. An organic light-emitting illumination apparatuscomprising: a first flexible substrate; a first electrode disposed onthe first flexible substrate and configured to transmit light; anintermediate layer disposed on the first electrode and comprising alight emission layer; a second electrode disposed on the intermediatelayer and configured to transmit light; a second flexible substratedisposed on the second electrode; a reflector interposed between thesecond flexible substrate and the second electrode to correspond to afirst region of the second flexible substrate; and a buffer layerinterposed between the second flexible substrate and the secondelectrode and between the reflector and the second electrode.
 2. Theorganic light-emitting illumination apparatus of claim 1, wherein: thebuffer layer corresponds to the first region of the second flexiblesubstrate and a second region of the second flexible substrate; and thesecond region comprises a residual portion of the second flexiblesubstrate other than the first region.
 3. The organic light-emittingillumination apparatus of claim 2, wherein a first thickness of thebuffer layer in the first region of the second flexible substrate isless than a second thickness of the buffer layer in the second region ofthe second flexible substrate.
 4. The organic light-emittingillumination apparatus of claim 1, wherein the buffer layer has anelastic characteristic.
 5. The organic light-emitting illuminationapparatus of claim 1, wherein the buffer layer comprises a holetransport material.
 6. An organic light-emitting illumination apparatuscomprising: a first flexible substrate; a first electrode disposed onthe first flexible substrate and configured to transmit light; anintermediate layer disposed on the first electrode and comprising alight emission layer; a second electrode disposed on the intermediatelayer and configured to transmit light; a second flexible substratedisposed on the second electrode; and a reflector interposed between thesecond flexible substrate and the second electrode to correspond to afirst region of the second flexible substrate, wherein the firstflexible substrate and the second flexible substrate are bent and foldeda plurality of times to provide a light emission area corresponding tothe reflector.
 7. The organic light-emitting illumination apparatus ofclaim 6, wherein a portion of the second flexible substratecorresponding to the reflector is not covered by the first flexiblesubstrate or other portions of the second flexible substrate.
 8. Theorganic light-emitting illumination apparatus of claim 1, wherein oneedge of the reflector is adjacent to one edge of the second flexiblesubstrate.